The present invention relates to lighting fixtures generally; it particularly relates to indirect lighting fixtures which illuminate a space by reflecting light off interior ceiling and wall surfaces.
The advantage of indirect lighting over direct lighting is in the ability of indirect lighting schemes to spread the light out over a larger area within a room and to do so more uniformly at a task surface whether the task surface is horizontal or vertical. Since before reaching the task area light is reflected off of a ceiling or wall surface, the light flux effectively comes to the task from a large area source equivalent to a large number of point source locations, resulting in an evenly lit task surface with minimum shadow. Indirect lighting also provides a more subtle and comfortable lighting environment by eliminating problems of glare which is the primary source of visual discomfort.
Despite its advantages, the choice of indirect lighting for space lighting presents certain disadvantages. For example, problems have existed in achieving light distribution patterns which avoid dark and/or bright spots on adjacent ceiling and wall surfaces. These problems have been addressed in applicant's copending application Ser. No. 46,950, filed June 8, 1979, wherein a unique lens design is provided to spread and more evenly distribute the fan of light from the fixture.
A further notable disadvantage of indirect lighting is psychological. It is found by the inventors that it is psychologically more pleasing for a person to have a perception of seeing the light source which produces general lighting, provided the source is not too bright. With conventional indirect lighting such a perception does not exist. This is because all the light from the light source is either directed upwardly above the horizontal plane of the fixture, or, if the light is directed below the fixture, it is directed against a wall adjacent the fixture to "wash" the wall with indirect light. In either case the person within the room is unable to locate the light source other than through wall and/or ceiling reflections.
The present invention pertains to long linear lighting fixtures, a style of fixture which generally employs fluorescent lamps as a light source but which can use other types of sources. For aesthetic reasons it is desirable to have in such a fixture a relatively small cross-sectional dimension of approximately 6 inches or less, for example, in the case of a cylindrically shaped fixture a diameter of about six inches. With significantly larger diameters the fixture becomes oversized in relation to many interior spaces in which the fixture is installed. The problem is that it is axiomatic that the smaller the dimensions of the fixture, and therefore the smaller the distances between the light emitting surfaces of the fixture lamps and the light control elements of the fixture, the more difficult it is to gain control over the distribution of light from the fixture. This control problem is acute in indirect lighting fixtures in the desirable fixture sizes above mentioned, that is, in fixtures employing conventionally sized lamps and having an overall cross-sectional dimension of approximately six inches. With indirect lighting fixtures having cross-sectional dimensions in the neighborhood of 9 inches, the problem of light control is not acute, however, the problem of visual proportion become the limiting factor.
The present invention is an indirect lighting fixture of cross-sectional dimension of approximately six inches which provides improved light control by providing the observer with a sense of seeing the source of light without introducing visual discomfort associated with direct lighting and excessive glare. Specifically, the fixture of the invention provides a perception of viewing the source of light by directing a controlled amount of light below the horizontal plane of the fixture. The invention in addition increases the overall efficiency of the indirect fixture whereby, with a given energy consumption, more light is available to meet lighting requirements. The present invention accomplishes the above objects with a fixture produced from conventional fabricating processes and with a fixture which is easily assembled and cleaned.